Probably keep the same Tree unlock conditions and Tree shape.
Probably done via swapping out the schematics in the nodes of the existing tree (the tree asset controls the dependencies so we don't have to worry about copying those over to our own schematics)
Probably keep the node's original unlock costs (these will have to be copied over from the vanilla schematic)
Complications:
How to handle "checkpoint nodes" that don't actually unlock anything?
AP support of nodes in MAM trees.
Complications: